public class Circle {	
		void printArea(double r){
		System.out.println(r*r*3.1415926);				
	}

}//圆的面积
class Rectangle{
	void printArea(double a , double b){
		System.out.println(a*b);
	}
}//正方形
class MainClass{
	public static void main(String args[]){
		Circle circle = new Circle();
		circle.printArea(100);
		Rectangle rect = new Rectangle();
		rect.printArea(100, 65);
	}
}//主函数
